1. I.Annelida A.Polychaeta Larva = TrochophoreLarva = Trochophore Band of cilia around body; tuft on apexBand of cilia around body; tuft on apex Same larval stage in Mollusca, Echiura, SipunculaSame larval stage in Mollusca, Echiura, Sipuncula Diverse lifestylesDiverse lifestyles Free-living predatorsFree-living predators Often well-developed eyes and sense organs, jawsOften well-developed eyes and sense organs, jaws Burrowing deposit feedersBurrowing deposit feeders Burrowing suspension feedersBurrowing suspension feeders Tube building suspension feedersTube building suspension feeders Tubes may be calcium carbonate, agglutinated or parchmentTubes may be calcium carbonate, agglutinated or parchment SolitarySolitary ColonialColonial

5. I.Annelida B.Oligochaeta Few marine speciesFew marine species Small organismsSmall organisms Benthic – mud and sandBenthic – mud and sand Deposit feedersDeposit feeders No parapodiaNo parapodia C.Hirudinea (Leeches) Few marine speciesFew marine species ParasiticParasitic No parapodiaNo parapodia

6. II.Mollusca More species (200,000+) than any other animal phylum except ArthropodaMore species (200,000+) than any other animal phylum except Arthropoda Soft bodySoft body Unsegmented, typically bilaterally symmetricalUnsegmented, typically bilaterally symmetrical Often protected by calcium carbonate shellOften protected by calcium carbonate shell Mantle secretes shellMantle secretes shell Ventral muscular footVentral muscular foot Many with head bearing eyes, sensory organsMany with head bearing eyes, sensory organs Radula – Ribbon of small chitin teeth used in feedingRadula – Ribbon of small chitin teeth used in feeding Gills for gas exchangeGills for gas exchange Many permutations on basic planMany permutations on basic plan Bivalves lack radulasBivalves lack radulas Squids have internal shellsSquids have internal shells Octopuses have no shellsOctopuses have no shells

7. Fig. 7.19

9. II.Mollusca A.Gastropoda (Class) Largest, most common, most diverse groupLargest, most common, most diverse group SnailsSnails Limpets - TerritorialLimpets - Territorial AbalonesAbalones Nudibranchs – Some store elements of dietNudibranchs – Some store elements of diet Shell often coiled (Exceptions ?)Shell often coiled (Exceptions ?) Ventral creeping footVentral creeping foot DietDiet Many vegetarian (scrape algae off rocks with radula)Many vegetarian (scrape algae off rocks with radula) Some predatorySome predatory Prey on bivalves, worms, fishes, spongesPrey on bivalves, worms, fishes, sponges

12. Nudibranchs with symbiotic algae

13. Fig. 7.20 Glaucus atlanticus

14. II.Mollusca B.Bivalvia Laterally compressedLaterally compressed Two-valved shellTwo-valved shell No headNo head No radulaNo radula Some have muscular foot for burrowing (How?)Some have muscular foot for burrowing (How?) Gills used for suspension feeding (active) & respirationGills used for suspension feeding (active) & respiration Water enters and leaves through siphonsWater enters and leaves through siphons Some anchor to substrate with byssal threadsSome anchor to substrate with byssal threads Largest mollusk (giant clam)Largest mollusk (giant clam) Shipworms (boring – use shells as rasps)Shipworms (boring – use shells as rasps) Common fouling organismsCommon fouling organisms Oysters – Produce pearlsOysters – Produce pearls Scallops – Swim!Scallops – Swim!

15. Fig. 7.22

16. II.Mollusca B.Bivalvia Laterally compressedLaterally compressed Two-valved shellTwo-valved shell No headNo head No radulaNo radula Some have muscular foot for burrowing (How?)Some have muscular foot for burrowing (How?) Gills used for suspension feeding (active) & respirationGills used for suspension feeding (active) & respiration Water enters and leaves through siphonsWater enters and leaves through siphons Some anchor to substrate with byssal threadsSome anchor to substrate with byssal threads Largest mollusk (giant clam – Tridacna gigas)Largest mollusk (giant clam – Tridacna gigas) Shipworms (boring – use shells as rasps)Shipworms (boring – use shells as rasps) Common fouling organismsCommon fouling organisms Oysters – Produce pearlsOysters – Produce pearls Scallops – Swim!Scallops – Swim!

17. Tridacna gigas Geoduck Video